Many diseases that affect organs develop over a decade or more. During this time, the function of the organ diminishes. The end-stage of many of these diseases is a transplant or some other treatment to supply artificially the organ's function—dialysis in the case of kidney disease such as end-stage renal disease, for example. A number of factors including immune system disorders or diabetes can cause these types of diseases.
Different diseases call for different treatments depending upon the dysfunction of the organ. For many of these diseases, the standard for treatment, short of a transplant, is drug-based. Drug-based treatments are usually systemic and typically use a pill or infusion of a solution of the drug in a carrier. These delivery methods are systemic because the patient's whole system is treated. But systemic treatment requires supplying the whole system drugs at levels high enough to be effective at the target organ. Achieving effective levels at the target organ frequently requires delivering toxic levels throughout the remainder of the system.
On the other hand, locally delivering the drug can alleviate some of the problems with systemic treatment. For instance, local delivery side-steps supplying the drug system-wide allowing for effective local drug levels while maintaining much lower system-wide levels, which are frequently benign to the patient.
But local delivery presents its own set of challenges. Typically, with local delivery, the drug enters the bloodstream upstream of the desired treatment site. Another technique involves injecting the drug into a (temporarily) unperfused region of the vasculature near or in the diseased organ. This technique can use an occlusion device upstream of the delivery region to inhibit or stop blood flow. In either case, the natural laminar flow of blood does not always promote effective mixing between the drug and blood.
Ineffective mixing can prevent the drug from evenly reaching its target organ or region's cells. For example, delivery upstream of an arterial branch coupled with ineffective mixing can result in more drug being delivered down one branch than another.
What is needed is a delivery technique for local delivery that provides effective mixing between the blood and the drug. This need is especially acute for delivery to the kidney because the kidney contains a highly branched arterial vasculature.